Slurry atomization of wheat-milled fractions for electrothermal atomic absorption spectrometric determination of nickel and chromium

A slurry electrothermal atomic absorption spectrometric technique was used to determine Ni and Cr in wheat flour and its by-products. Slurries (3%, w/ v) were prepared in a mixture of 15% HNO3-10% H2O2 as suspended medium. Dif ferences in Ni and Cr contents due to origin and texture of the wheat and t o the effects of the milling process were studied. Ni and Cr levels were mo re markedly influenced by the geographical origin of the wheat than by its texture. Both metals were related to the amount of bran present in each mil led fraction and varied over the ranges of 212-298 ng/g (Ni) and 34-85 ng/g (Cr) in flours (with minimal bran contents); 297-460 ng/g (Ni) and 67-118 ng/g (Cr) in shorts; and 424-723 ng/g (Ni) and 106-165 ng/g (Cr) in brans. The Ni and Cr contents were not significantly affected by the technological processes typically performed in a flour-producing factory.